Effect of Hempseed Cake Instead of Cottonseed Meal on Ghrelin and Growth Hormone in Lambs

Abstract

The aim of this study was to determine plasma ghrelin and growth hormone levels in lambs fed cottonseed meal (CSM) and hempseed cake (HSC) and to determine the relationships between these levels and fattening performance. The lambs were randomly distributed to the control and treatment groups with ten lambs in each group. The control group lambs were fed with a ration containing CSM as protein source and the treatment group lambs were fed with a ration containing HSC. Live weights were recorded at the beginning of the acclimation period and on days 0, 30 and 60 of feeding. Serum ghrelin and growth hormone were measured by ELISA from jugular blood samples taken pre-feeding on the same days. No significant differences were determined between groups in live weights at different periods. Ghrelin hormone concentrations measured at the beginning of the acclimation and on days 0, 30, and 60 were 66.26 and 94.07 ng/ml, 56.66 and 77.19 ng/ml, 71.52 and 93.28 ng/ml (p<0.01), 67.96 and 54.59 ng/ml in control and treatment group lambs, respectively. Growth hormone concentrations measured during the same periods were 1.92 and 3.06 ng/ml (p<0.05), 1.96 and 3.33 ng/ml (p<0.05), 2.86 and 3.98 ng/ml, 5.19 and 5.50 ng/ml in control and treatment groups, respectively. Low correlations were found among ghrelin, growth hormone, and live weight. Consequently, hempseed cake was a viable source of protein for lambs, promoting growth and causing a transient rise in ghrelin levels that subsided by day 60. The biological mechanisms driving these hormonal changes -potentially involving cannabinoids- warrant further investigation.